Passive buffer brush air cooling

ABSTRACT

In one embodiment, the present invention provides a buffer brush. When rotating, the buffer brush acts as a centrifugal pump. The buffer brush contains a core having a first side and a second side and the brush extends racially from the surface of the core. The first and second sides have at least one opening configured to allow air to flow laterally through the core. Vents on the surface of the cure are configured to allow air flowing laterally through the core to also flow radially through the vents into the brush.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is a divisional of copending U.S. patentapplication Ser. No. 12/629,486, filed Dec. 2, 2009, which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

Buffer brushes are used in a variety of applications. For example,buffer brushes are used for removing the tread of worn tires. Tirebuffing is part of the tire retreading operation. However, bufferbrushes used in the process of removing the tread of worn tires oftenwear out and must be replaced frequently. Buffer brushes are also usedto add texture to the surface of a newly manufactured tread.

Typically the tire casing selected for retreading is buffed to removeexcess rubber to provide a substantially evenly textured crown forreceiving a tread strip and to provide a predetermined tire casingprofile. Prior to retreading, the casing must be buffed, generally to apredetermined characteristic crown radius corresponding to the uppercontour of the belt package. The casing is buffed to leave only apredetermined thickness of material remaining over the top belt. Theshoulder of the casing is also buffed to eliminate or reduce voids orpatterns in the shoulder created by the original tread, and to provide arelatively straight profile between the casing side walls and the crown.A worn casing from each of the various models and sizes of new tires hasa characteristic tire casing profile of a particular crown width, crownbuffing radius and should trim angle which must be created as an initialstep in the buffing process.

In present retreading processes, it is important that the surface of thetire casing be carefully buffed about the shoulder areas of the tire toensure that the tread layer width is approximately the same as thebuffed surface of the casing. If the shoulder areas are not sufficientlybuffed and trimmed, the tread edges may come loose and/or the cushiongum extending beyond the tread edges will not bond to the casingshoulder. Such problems can reduce the longevity of the retreaded tireand adversely impact the appearance of the retreaded tire.

The tire casing is buffed to remove tread material and to achieve adesired surface texture. Typically, it is desired for the crown and theshoulders of the tire casing to have different textures. The surfacetexture can be measured on a visual scale propounded by the RubberManufacturer's Association (RMA) with a numerical value between 1 and 6with 1 being the finest and 6 being the roughest texture. Typically, itis desired for the crown of the tire casing to have a RMA number ofbetween 3 and 4 and for the shoulder to have an RMA number of about 2.The shoulders of the tire casing typically are subjected to the largeststresses encountered by the tire during service. The finer texture onthe shoulders promotes better adhesion of the tire tread to the casingat these high stresses. If the shoulders received too much texturing,crack propagation in these areas is more likely. In instances where theshoulder receives too little texturing, the bond between the tire casingand the tread is poorer.

The current state of the art in tire casing buffing allows for amultiplicity of tread removal passes, substantially in a sideways, passafter pass method. U.S. Pat. No. 6,745,809 to Mory et al. and assignedto Bandag Licensing Corp. describes a tire buffing apparatus and isincorporated herein in its entirety for everything that it teaches.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the present invention provides a buffer brush. The bufferbrush contains a core having a first side and a second side and thebrush extends radially from the surface of the core. The first andsecond sides have at least one opening configured to allow air to flowlaterally through the core. Vents on the surface of the core areconfigured to allow air flowing laterally through the core to also flowradially through the vents into the brush.

In another aspect, a buffer brush is provided having a first end platewith a plurality of openings and a second end plate with a plurality ofopenings. At least one brush segment comprises a core having openingsconfigured for lateral air flow and vents configured for radial air flowand brush bristles extending radially from the core. The brush segmentis mounted between the first end plate and the second end plate andconfigured such that air can flow through the openings in the first endplate and the second end plate and through the openings configured forlateral air flow and vents configured for radial air flow.

Another aspect of the invention provides a method of buffing. A bufferbrush is provided. The brush contains a core having a first side and asecond side and the brush extends radially from the surface of the core.The first and second sides have at least one opening configured to allowair to flow laterally through the core. Vents on the surface of the coreare configured to allow air flowing laterally through the core to alsoflow radially through the vents into the brush. The brush is rotatedsuch that air flows laterally through the core and radially through thevents.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 illustrates one embodiment of a brush assembly including endplates having vent openings;

FIG. 2 illustrates one embodiment of a brush segment that may be used toconstruct the brush assembly illustrated in FIG. 1;

FIG. 3 illustrates one embodiment of air flow through the brush segmentillustrated in FIG. 2;

FIG. 4 illustrates multiple brush segments and endplates forming thebrush assembly.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the teachings of the present invention, a bufferbrush is provided. In one embodiment, the buffer brush is used in a tirebuffing apparatus. However, the buffer brush may be used in a variety ofapplications and is not limited to tire buffing.

Turning now to the figures, an illustrative embodiment of a brushassembly 100 including end plates 102 having openings 104 is shown inFIG. 1. In the illustrated embodiment, an axel 106 traverses the brushassembly 100 laterally through the brush assembly's core 108. In oneembodiment, the brush assembly 100 includes brush bristles 110 extendingradially from the core 108. The rotation of the brush assembly 100 actsas a centrifugal pump. Air is pulled through the openings 104 in theendplate 102. The air traverses the brush laterally through the core 108and vents through the brush bristles 110. During a buffing operation,the brush bristles 110 may become warmer than the ambient temperature.The air venting through the brush bristles 110 cools the bristles andmay extend the brush life.

The brush assembly 100 may be constructed using one or more brushsegments. FIG. 2 illustrates one embodiment of a brush segment 112 thatmay be used to construct the brush assembly 100 illustrated in FIG. 1.FIG. 2 shows only a portion of the brush segment 112. In one embodiment,the brush segment 112 includes brush bristles 114. The core 116 may beconstructed from metal, plastic or other suitable material forsupporting the brush bristles 114. Openings 118 in the core 116 allowair to traverse laterally through the assembled buffer brush assembly100 (FIG. 1). Vents 120 allow air traversing laterally though the coreto escape radially through the brush bristles 114.

FIG. 3 illustrates one embodiment of air flow through the brush segmentillustrated in FIG. 2. As the brush assembly rotates, centrifugal forcespump air through the openings 118 in the core 116. The air escapes fromthe core 116 through vents 120. One illustrative example of air flowthrough a vent 122 and the brush bristles 114 is shown. Pumping airthrough the openings 118 in the core 116 and through the vents 120collects any dust that is generated during buffing. For example, buffingthe tread from a tire may result in small rubber particles or dust. Airflowing through the brush bristles 114 helps force the dust out of thebrush. In an alternative embodiment, the brush bristles 114 may havelarger openings or cuts to allow additional air flow from the vents 120.

FIG. 4 is a cross sectional view of multiple brush segments andendplates forming the brush assembly 100 illustrated in FIG. 1. In thisembodiment, an axel 124 traverses the brush assembly 100 laterallythrough the brush assembly's core 126. End plates 128 contain openings130, allowing air to enter the brush assembly's core 126. In thisembodiment, the brush assembly 100 is formed from a plurality of brushsegments 132. The brush segments include brush bristles 136 and a brushsegment core 138. The brush segment cores 138 contain holes (not shown)that allow air to traverse the brush assembly core laterally and vents(not shown) that allow air to vent radially through the brush segmentbristles 136. When spinning, the brush acts as a centrifugal pump,pulling air through the end plate 128 openings 130. The air traversesthe brush assembly's core 126 through openings in the brush segment 132core 138. The air is vented through the brush bristles 136 through ventsin the brush segment 132 core 138. Pumping air through the brushbristles cools the bristles, thus extending the brush life.Additionally, dust and other particles are removed from the bristles 136and can be collected.

As one example application, the buffer brush can be used in a tirebuffing apparatus for buffing a tire casing as part of a retreadoperation. The tire buffing apparatus can include a base assembly, arasp pedestal, a moving assembly, a tire hub assembly, an operatorstation associated with a control unit, an electrical enclosure, and apneumatic enclosure. The rasp pedestal can include a rasp head and atexturing device, such as the buffer brush, mounted to a single shaftfor rotation thereabout. The rasp pedestal can rotate about a verticalaxis. The moving assembly can be mounted to the base assembly andconnected to the rasp pedestal for selectively moving the rasp pedestalalong a pair of perpendicular horizontal X and Y axes. The tire hubassembly can be included for rotating the tire casing. The tire buffercan be operated at the operator station by interfacing with the controlunit, which can be housed in the electrical enclosure. The tire buffercan include a tire location mechanism mounted to the rasp pedestal fordetecting a tire casing mounted to the tire hub assembly when the rasppedestal is within a predetermined distance of the tire casing. A tiremeasurement mechanism can be mounted to the pedestal for measuring thesize of the tire casing mounted to the hub assembly.

The tire buffer can automatically buff a tire casing to achieve apredetermined tire casing profile and impart a texture thereto. Thecontrol unit can be associated with a current sensor which senses thecurrent draw of a rasp drive motor for rotating the rasp head and thetexturing device. During the buffing sequence, the control unit cancompare the actual current draw of the rasp drive motor to apredetermined target current draw and adjust an operating characteristicof the tire buffer, such as the traverse speed of the rasp pedestalacross the width of the tire casing being buffed, in response to anydifference therebetween to urge the actual current draw toward thetarget current draw. In other embodiments, the operating parametermonitored and/or the operating characteristic that is changed to changethe monitored operating parameter can be varied.

The tire buffer can automatically impart a predetermined shouldertexture upon shoulders of the tire casing being buffed with thetexturing device. The tire buffing apparatus is fully detailed in U.S.Pat. No. 6,745,809 to Mory et al. which is assigned to Bandag LicensingCorp.

In a second exemplary application, the buffer brush can be used as partof a process to add texture to newly manufactured tread. In oneembodiment, tread is molded into flat 35 foot long sections. Thesesections have a smooth surface. The tread sections are processed througha series of buffers to remove the smooth surface and texturize thesurface of the tread.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

The invention claimed is:
 1. A method for manufacturing a retreaded tirecomprising: providing at least one buffer brush comprising: a first endplate having a plurality of openings and a second end plate having aplurality of openings; at least one brush segment comprising a brushsegment core, the at least one brush segment core forming thereinopenings that allow air to traverse the brush segment core in a lateraldirection and disposed at a radial distance from a rotational axis ofthe at least one brush segment, vents communicating with the openingsand configured for radial air flow, each of the vents being incommunication with at least two of the openings formed in the brushsegment core, and brush bristles extending radially from the brushsegment core; the at least one brush segment mounted between the firstend plate and the second end plate and configured such that air can flowthrough the openings in the first end plate and through the openings inthe second end plate and through the openings formed in the brushsegment core, the openings in the brush segment core configured forlateral air flow and the vents configured for radial air flow; coolingthe buffer brush by rotating the buffer brush such that air flowslaterally through the openings in the brush segment core and radiallythrough the vents; processing a tread section through the at least onebuffer brush such that the processed tread section has a texturizedsurface; buffing a tire casing such that a worn tread is removed fromthe casing; and applying the tread section to the tire casing.
 2. Themethod of manufacturing according to claim 1 wherein the brush segmentcores of a plurality brush segments comprise a brush assembly core. 3.The method of manufacturing according to claim 1 wherein the step ofbuffing a tire casing further comprises using the at least one bufferbrush to buff the tire casing.
 4. The method of manufacturing accordingto claim 1 wherein the buffer brush is a wire brush.
 5. The method ofmanufacturing according to claim 1 wherein the step of rotating furthercomprises rotating the buffer brush with an electric motor.